These interrelated studies have as their goal the identification of risk factors for oral and pharyngeal cancer and identification of factors that influence detection of oral cancer or of persons at highest risk of these cancers. One study is of persons with white or red oral mucosal lesions seen at six Department of Veterans Administration (VA). Study subjects undergo a biopsy of all suspect oral lesions, provide information about tobacco, alcohol intake, and other habits and re-examined periodically. Efforts are underway on how behavioral (e.g., tobacco, alcohol factors, p53 suppressor genes, human papilloma virus, mutations, and genes that may affect carcinogen metabolism influence the clinical and histological presentation and course of these lesions. This study may be useful identifying persons who should be monitored most closely for the development of oral cancer and to recognize oral cancers at the earliest, most treatable stage. The SEER/Medicare Linkage project merges two complex databases: the Medicare statistical system and a data system containing information on cancer cases diagnosed and reported in nine geographically distinct population-based tumor registries. NIDCR is collaborating with the NCI to analyze patterns of health care and health care costs among 30,000 persons 65 years of age and older prior to and subsequent to a diagnosis of oral, pharyngeal, or laryngeal cancer. This work addresses: determinants of early stage of cancer at diagnosis, determinants of treatment choices, patterns of treatment and rehabilitation after oral, pharyngeal, or laryngeal cancer, and patterns of morbidity and mortality associated with these cancers. The principle purpose of the third study is to identify sociodemographic, behavioral, nutritional, dental, and occupational risk factors for oral and pharynx cancers in Puerto Rico. In addition, the study will evaluate the role of human papilloma virus, carcinogen-metabolizing alleles, and biomarkers for malignancy and malignant transformation using biological specimens from cases and controls. This large, population-based case-control study provides insights into the etiology of oral and pharyngeal cancer and the reasons for the high incidence rates of these cancers in Puerto Rico.